Missing palette entry for index 5

Hello, was running a Minecraft server on my Raspberry Pi 4, but now when I restart it and enter a certain chunk that has not loaded, an error pops up in my server logs. The Minecraft server isn't even able to /stop any more, it gets stuck on "Saving worlds" for at minimum, an hour with a high CPU usage while doing so. Before this, it was saving within a matter of 4 minutes. I am writing this while it is happening and it is just impressive to see what is going on here.

latest.log file is attached. Please ignore our conversation and just pay attention to the errors.

Any ideas on what I should do? I am too scared to force quit the save process as it looks like it is editing the world folders from using the luser command on my machine.